For industries operating in the marine environment biofouling, i.e. the unwanted colonization of man-made structures by bacterial slimes, macroorganisms and macroalgae, has significant economic implications. Submerged surfaces such as water pipes, power plant water intake systems, sewer pipes, boat hulls, propellers, heat exchangers, grids, fish nets and cages, and the like are prone to marine biofouling. Aquatic pests frequently clog pipes or become attached to submerged surfaces and thus interfere with normal operations. For example, warm water associated with power plant cooling systems provides an ideal environment for the attachment and growth of aquatic organisms. Biofouling organisms also attach to other surfaces in the aquatic environment such as fishing nets, buoys, pilings, off-shore platforms, lumber, and concrete. When a clean surface is introduced into an aquatic environment, it typically becomes coated with a conditioning layer of hydrophobic dissolved organic compounds (Rittschof D. 1997 In Fingerman M et. al. (eds) Recent advances in marine biotechnology, Vol. 3. Science Publishers, Inc., NH, pp. 245–257). Microorganisms such as bacteria, algae, fungi, and protozoa attach to the conditioning layer and establish colonies, which result in the formation of a slime layer (Clare et al., 1992 Invert Reprod Dev 22:67–76). Such slimes contribute to the establishment of biofouling communities because planktonic (free floating) larvae of many invertebrate biofouling organisms are physically and chemically attracted to the slime layer (Wieczorek et al., 1997 Mar Ecol Prog Ser 119:221–226). Biofouling organisms with a calcareous shell or tubes are particularly troublesome and include mussels, tubeworms and barnacles. Biofouling of underwater structures results in significant economic losses to industry. Decreased fuel efficiency, increased cleaning and maintenance expenses, as well as outage expenses all contribute to increased economic expenditures (Rittschof D. 1997 In Fingerman M, Nagabhushanam R, Thompson M-F (eds) Recent advances in marine biotechnology, Vol. 3. Science Publishers, Inc., NH, pp. 245–257).
The incentive for preventing marine biofouling is great. As a result, various methods and compositions have been developed for the prevention of marine biofouling. For example, utilities employ several methods for removing established biofouling communities. Periodic power outages are employed to physically enter power plant systems to remove organisms and debris. In addition, utilities often attempt to kill established biofouling communities by pumping large volumes of chlorine or other biocides through water handling systems. However, these methods are slow acting and adversely affect the local ecology downstream from the effluent. Furthermore, these chemical treatments are inefficient because toxins are mixed in bulk water phase in an attempt to treat a surface phenomenon. Another drawback of certain existing chemical treatments is that relatively large toxic doses must be maintained for extended periods to effectively eliminate biofouling pests (Rittschof D. 1997 In Fingerman M, Nagabhushanam R, Thompson M-F (eds) Recent advances in marine biotechnology, Vol. 3. Science Publishers, Inc., NH, pp. 245–257). Ablative toxic antifouling coatings containing tributyl tin, copper alloys, mercury compounds, or cathodic protection have also been employed to control fouling. These antifouling coatings include toxins, which are leached into the aquatic environment to inhibit biofouling (Rittschof D. 1997 In Fingerman M, Nagabhushanam R, Thompson M-F (eds) Recent advances in marine biotechnology, Vol. 3. Science Publishers, Inc., NH, pp. 245–257). The most widely used chemical antifoulant compound is tri-n-butyl tin (TBT). High concentrations of TBT have been found in sediments particularly in harbors and along commercial shipping routes (Hashimoto et al., 1998 Mar Environ Res 45: 169–177). The adverse effects of TBT and its' derivatives on the marine environment have been recognized for some time, particularly their androgenic effect (Fisher et al. 1999 Mar Environ Res 47: 185–201; Mathiessen P., Gibbs P. E. 1998 Environ Toxicol Chem 17: 37–43). In response to these concerns Marine Environment Protection Committee (MEPC) of the International Maritime Organization (IMO) has developed an instrument to ban the application of tributyltin paints from 1 Jan. 2003, with the intent that no TBT paints will remain on vessels after 1 Jan. 2008 (http://www.imo.org/conventions).
Vessels are increasingly painted with copper-based paints as an alternative to TBT paints. However, these “alternatives” have negative effects on the marine environment, too, e.g. oysters accumulate considerable amounts of copper and it is toxic to marine algae (Claisse & Alzieu 1993 Mar Pollut Bull 26: 395–397). Concerns about the toxicity of not only TBT, but also all antifouling biocides has stimulated research and development of non-toxic, fouling release coatings. Therefore, the development of a marine paint or paint ingredient that is non-toxic, non-heavy-metal-based and benign to the marine environment is urgently sought. A preemptive antifouling composition is needed for treating surfaces in aquatic environment in a highly effective manner.
It is therefore an object of the present invention to provide a method of producing an anti-fouling agent and a composition derived therefrom.